Pbessttke-gage



T. A. NELSON.

PRESSURE GAGE.

APPLICATION FILED APR. 7. 1911.

1,322,463,, 7 Patented Nov. 18, 1919.

. to form an opening to the accompanying drawing,

THOMAS A. NELSON, 0

F CHICAGO, ILLINOIS.

PRESSURE-GAGE.

Application filed April 7, 1911.

To all whom it may concern:

Be it known that I, THOMAS A. NELSON, a citizen of the United States,residing at Chicago, in the county of Cook and State of Illinois, haveinvented new and useful Improvements in Pressure-Gages, of which the.following is a full, clear, concise, and exact description, referencebeing had to forming a part of this specification. I

My invention relates to improvements in gages.

It is one of the objects of my invention to provide a pressure vacuum orcompound gage which will read accurately under all conditions.Heretofore in the commercial art pressure gages have been so constructedthat in fastening them in position on the end of the pressure pipe theconnections are strained or twisted tp such an extent that the Bourdontube has been thrown out and the gage caused to register inaccurately,sometimes as much as five or ten pounds or more.' In fact, most gages asnow'commercially constructed are not accurate after they have once beenplaced in position, due to this very fact that they are strained inbeing secured to the pressure pipe. It is one of the objects of myinvention to overcome the above defects.

Another object of my invention is to pro vide a gage in which the partsmay be readily removed for the purpose of inspection or repair withoutdisconnecting the entire gage from the. pressure pipe or removing thecasing from position. Other objects and advantages of my invention willappear in the following specification and drawings.

For the purpose of disclosing my invention I have illustrated certainembodiments thereof in the accompanying drawings. In said drawings,

Figure 1 is a sectional view of a gage embodyin my invention; and,

Fig. 2 is a sectional view taken on the line 6-6 of Fig. 1.

In the embodlment of my invention illustrated I provide-an inclosingcasing having a dial face 2 and glass cover 3. At the lower part of thecasing the side is drilled permit the extension therethrough of a 1pcfitting 4. This pipe fitting is provide with a pair of flanges 5 intowhich are adapted to screw the retaining screws 6 to hold the pipefitting in place and the extremity of the fitting is Specification ofLetters Batenfi to be adjusted for varying constructed in Patented Nov.18, 1919. Serial No. 619,563.

screw threaded, as at 7 to connect with the pressure pipe.

The operating mechanism of the gage is all mounted upon a singleindependent plate 8 which may be secured either to the back of thecasing or may be secured to the front dial of the casing, as shown. Thisplate carries the usual operating mechanism of a gage, which consists ofa Bourdon tube 9 closed at one end by a cap 10, which cap is providedwith an car 11 connected by a link 12 with the stem 13 of a segmentalrack 14. The segmental rack is preferably pivoted between the upperplate 16 and the plate 8 and the stem 13 thereof is made in two parts,slotted and set screws to permit the length of the stem conditions. Thisrack 14 is adapted to mesh with a pinion 19 mounted on a stem arrangedbetween two plates and projecting through the dial plate to carry thepointer 20. A hair spring, one end of which is connected to one of theposts of the plate and the other end of which is connected to the stemof the pinion 19, tends to maintain the pointer at its zero point. Theopposite end of the Bourdon tube is connected in a supporting socket 21,suitably secured to the plate 8 by screws' This socket is bored to forma continuous opening and one end of the Bourdon tube is screwed into oneend of the opening, the 0pposite end of the opening being connected by aflexible pipe 24 with the pipe fitting 4:. Th flexible connectionpreferably takes the form of a copper or lead pipe and is connected tothe socket and fitting as shown. The socket is bored and internallyscrewthreaded as at 25 and the pipe 24 is passed through a centralopening in a threaded nipple 26. The end of the pipe is then swaged overthe nipple and the nlpple 26 screwed down into the threaded opening 25,thereby securely clamping the swage end of the pipe in position asshown. Th s arrangement makes a perfectly secure tightsecured togetherby fitting joint and at the same time permits the ready removal of theparts. a

By the interposition of a flexible condult between the pipe fitting andthe Bourdon tube I eliminate a number of the objection= able featuresheretofore found in pressure gages. Heretofore ressure gages have beensue a manner that the Bourdon tube 1s rigidly connecteddirectly to andmounted upon the pipe fitting, and

I tent that it Will frequently register plate, and then, by

.I have found in practice that due a; this manner of connection theBourdon tube is strained when the fitting is connected to the pressurepipe and the connection so twisted he gage is thrown out to such anexwrong from five to ten pounds. By the interposition of a flexibleconnection, as illustrated,

sure pipe this strain and alinement of the pipe fitting will not affectthe Bourdon tube, the strain and twisting action being taken up by theflexible connection 24. Furthermore, seen that due to this flexibleconnection the working parts of the gage maybe removed withoutdisconnecting the gage from its pressure pipe. All that is necessary isto remove the outer securing ring 3 of the casing, take oil the topglass, take oil the dial taking out the screws securing the plate 8 inposition on the back 0 th the plate may be readily lifted the flexiblepipe permitting this Withing, the flexible pipe may nected from the pipefitting by unscrewmg the little nipple 26. It frequently happensinpressure gages WlllCh operate in the open air: that the water ofcondensation-settles in the lower bend of the tube when the gage is'used for registering steam pressure, and in cold weather freezes. It isalmost impossible with the present commercial gage to thaw this gage outexcept by entirely removing By th be readily disconthrough aw the tubeout.

through close thetube when frozen.

In the structure illustrated, in addition to the Bourdon tube I providean interior tube 38 for the Bourdon tube. This tube is preferably madeof flexible material and, as shown, is of smaller diameter than theBourextending clear up to the free end e inner end of the tube 38 is theflexible connection};

con- 4. In addition to I provide a blow-oft plpe fitting is it willreadily be the tube, thereby blowing out the greater part ofthe water ofcondensation l which secures the end port 39, which is connec'tedwith ablow-off valve, 40 mounted on the casing, by a'flexi'ble connection 41and provided with a key 42,

- whereby the same may be opened and closed.

In ordinary practice the valve 40 is kept closed, but when it is desiredto clean out the Water of condensation in the tube the valve 40 isopened and the live steam passing through the Bourdon tube will thenblow the water of condensation out through the connection 41 theatmosphere.

I have also provided a sprin supporting the free end of t As thisespecially adapted for railway locomotive work, and as in gages of thischaracter the constant jarring of the locomotive tends to cause-the freeend of the tube to vibrate, thereby causing the indicator of the gage toflicker, I flexibly connect the free end of the tube with a stationarypost. In the structure shown this flexible connection consists of a coilspring 43, one end of which is secured to the ear 11 of the Bourdon tubeand the other end of which is connected to a stem 44 adapted to passthrough a projection 45and have secured on its opposite end ascrew-threaded nut 46. By thls arrangement, While the expansion andcontraction of the Bourdon tube is not affected, the free end ispreventedfrom rapidly vibrating and causin a flickering of theindicator.

i e I have described my age as being particularly applicable forinficating pressure, it will be understood 'that the same may be used asa compound gage, or as a vacuum indicating gage, and where I have usedthe expression expansion tube in the claims and in the specification,itvwill be .understood that this is for the purpose of describing thecharacter of the tube rather than the specific function.

While I have illustrated and. described certain embodiments .of myinvention, it will be understood that various modifications and changesmay be made therein without departing from the spirit of my invention asembodied in the appended claims.

Having thus described my invention, what I claim as new and desire tosecure by Letters Patent is: 1 j

1. In a device of the character described, the combination with anexpansion tube means ,for e Bourdon particular form of tube is closed atone end and having a normally I tially the entire length of the tube,having one end opening in the expansion tube and the other end connectedwith the pressure supply.

.2. In a gage, the combination with an tube closed at one end and havingexpansion at the other end a valve-controlled opening opening to theatmosphere, of a second tube arranged within said expansion tube andextending substantially the entire length of the expansion tube, one endthereof opening in the expansion tube and the other end being connectedwith the pressure supply pipe.

3. In a gage, the combination with a con-' nection fitting, of anexpansion tube and indicating mechanism, a valve opening to theatmosphere, a flexible conduit extending between said valve second tubearranged within said expanslon tube of substantially the same length asthe expansion tube, one end thereof opening in the expansion tube, and aflexible connection between said connection fitting and said secondtube.

4. In a gage, the combination with a casand expansion tube, a

ing, of a connection fitting mounted on said casing, a Bourdon tube andan indicating mechanism arranged within said casing, a second tube ofsubstantially the same length as the expansion tube arranged within saidexpansion tube and having one end opening within the expansion tube. aflexible conduit connection extending between said second tube and :theconnection fitting, a valve mounted on said casing opening to theatmosphere, and a flexible conduit connection extending between saidvalve and the expansion tube.

In witness whereof, I have hereunto subcribed my name in the presence oftwo witnesses.

- THOMAS ANELSON.

' Witnesses:

E. R. KING, Y W. PERRY HAHN.

